1. Field of the Invention
The invention relates to a wireless communications circuit, more particularly to a radio frequency (RF) circuit system and a method for increasing isolation between two wireless communications standards within an RF circuit system.
2. Description of the Related Art
Because of the market's increasingly advanced requirements for wireless communications devices, many terminalable wireless communications devices, such as smart phones, have been integrated with multiple communications standards, such as WiFi, EDGE, HSPA, EV-DO, LTE, or Bluetooth. However, the space available for internal circuitry is limited. Since the hardware for these different wireless communications standards are in proximity to each other, the isolation between these standards is often insufficient, thus creating interference amongst themselves.
As shown in FIG. 1, when two wireless communications modules 100, 200, such as LTE and WiFi, are integrated into a single wireless communications device, the distance and isolation between the two wireless communications modules 100, 200 become fixed. Thus, the schematics of the wireless communications device itself could create insufficient isolation (both circuit isolation and antenna isolation) between the two wireless communications modules 100, 200. In this case, when the wireless communications modules 100, 200 are simultaneously in operation within the same wireless communications device, interference between the wireless communications modules 100, 200 could diminish the functionalities of one or both of the wireless communications modules 100, 200. When the operating band for an RF module 101 for the wireless communications module 100 overlaps with the operating band of the wireless communications module 200, the side lobes of a signal transmitted using the wireless communications module 100 could interfere with at least part of the operating band of the wireless communications module 200, and typically the wireless communications module 200 is unable to adjust around the interference, thus hindering its the ability to function.